Biodiversity as insurance
Diversity buffers against changes
No one species fills all the roles (functions) of an ecosystem (species diveristy)
No one individual has all the alleles for a gene (genetic diversity)
Today’s topic: Species Diversity
- Intricate webs of interacting organisms
- 2,000,000 species are known
- ~18,000 new species discovered per year
- estimated >85% of species unknown
- Reflects billions of ways organisms have adapted, over and over, to a changing planet
- biodiversity ’hot spots” exist
- Humans relentlessly alter ecosystems
- aquatic and terrestrial
- ~150 species go extinct each day
HOW: Measuring biodiversity (e.g. Simpson’s index)
Assumption: All species are equally important
Richness and Evenness both contribute to functional diversity
WHO: Species types (native, endemic, non-native, invasive)
The march of the cane toad
Where: Species diversity declines from tropics
Where: Species diversity declines at altitude
Mapping biodiversity: Soil community diversity matters
Mapping biodiversity: Oceans
Ecoregions: Where biodiversity hotspots exists
Hotspots: Andean uplift and bird diversity
Hotspots: Endemic species of Madagascar
What factors contribute to 90% endemism?
Threats to biodiversity
Threats: Invasive species are increasing
- Change physical and biotic environment
- Aquatic ecosystems heavily affected
- Impacts outweigh natural extinction rates
Ecoregions versus humans
